docs: def set_dtreat_indt(self, t=None, indt=None):
          """ Store the desired index array for the time vector
  
          If an array of indices (refering to self.ddataRef['t'] is not provided,
          uses self.select_t(t=t) to produce it
  
          """
          lC = [indt is not None, t is not None]
          if all(lC):
              msg = "Please provide either t or indt (or none)!"
              raise Exception(msg)
  
          if lC[1]:
              ind = self.select_t(t=t, out=bool)
          else:
              ind = _format_ind(indt, n=self._ddataRef['nt'])
          self._dtreat['indt'] = ind
          self._ddata['uptodate'] = False